A radar system is provided that includes transmission signal generation circuitry, a transmit channel coupled to the transmission generation circuitry to receive a continuous wave test signal, the transmit channel configurable to output a test signal based on the continuous wave signal in which a phase angle of the test signal is changed in discrete steps within a phase angle range, a receive channel coupled to the transmit channel via a feedback loop to receive the test signal, the receive channel including an in-phase (I) channel and a quadrature (Q) channel, a statistics collection module configured to collect energy measurements of the test signal output by the I channel and the test signal output by the Q channel at each phase angle, and a processor configured to estimate phase and gain imbalance of the I channel and the Q channel based on the collected energy measurements.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A radar system comprising: circuitry configured to generate a continuous wave signal; a transmit channel coupled to the circuitry, the transmit channel configured to: receive the continuous wave signal; generate a first test signal based on the continuous wave signal, the first test signal having a first phase angle; and generate a second test signal based on the continuous wave signal and the first test signal, the second test signal having a second phase angle, wherein the first phase angle and the second phase angle are in a phase angle range and a phase difference between the first phase angle and the second phase angle is a descrete step size; a receive channel coupled to an output of the transmit channel via a feedback loop, the receive channel configured to: receive the first test signal; generate a first in-phase (I) channel test signal in accordance with the first test signal; generate a first quadrature (Q) channel test signal in accordance with the first test signal; receive the second test signal; generate a second I channel test signal in accordance with the second test signal; and generate a second Q channel test signal in accordance with the second test signal; a statistics collection module coupled to the receive channel, the statistics collection module configured to: receive the first I channel test signal; measure energy of the first I channel test signal; receive the first Q channel test signal; measure energy of the first Q channel test signal; receive the second I channel test signal; measure energy of the second I channel test signal; receive the second Q channel test signal; and measure energy of the second Q channel test signal; and a control module coupled to the statistics collection module, the control module configured to determine phase and gain imbalance of the I channel and the Q channel based on the energy of the first I channel test signal, the energy of the first Q channel test signal, the energy of the second I channel test signal, and the energy of the second Q channel test signal.
2. The radar system of claim 1 , further comprising a power detector coupled to the feedback loop, the power detector configured to measure power of the first test signal and power of the second test signal.
3. The radar system of claim 1 , wherein the phase angle range is 0° to 240° and the discrete step is 15°.
4. The radar system of claim 1 , wherein determining the phase and gain imbalance comprises: determining an I channel energy peak from the energy of the first I channel test signal and the energy of the second I channel test signal; determining a Q channel energy peak in accordance with the energy of the first Q channel test signal and the energy of the second Q channel test signal; determining a power of the first I channel test signal; determining a power of the first Q channel test signal; determining a power of the second I channel test signal; determining a power of the second Q channel test signal; determining an I channel power peak in accordance with the power of the first I channel test signal and the power of the second I channel test signal; determining a Q channel power peak in accordance with the power of the first Q channel test signal and the power of the second Q channel test signal; and computing the gain imbalance in accordance with the I channel energy peak, the Q channel energy peak, the I channel energy power peak, and the Q channel power peak.
5. The radar system of claim 4 , wherein determining the I channel energy peak and the Q channel energy peak further comprises: determining an I channel coarse energy peak from the energy measurements of the I channel and of a Q channel coarse energy peak from the energy measurements of the Q channel; and interpolating around the I channel coarse energy peak and around the Q channel coarse energy peak to determine the respective I channel energy peak and Q channel energy peak.
6. The radar system of claim 5 , wherein an order of the interpolation is quadratic.
7. The radar system of claim 5 , wherein determination of an I channel coarse energy peak and a Q channel coarse energy peak comprises selecting a largest energy measurement from the respective energy measurements having a previous energy measurement and a subsequent energy measurement as the respective coarse energy peak.
8. The radar system of claim 4 , wherein determining a test signal power measurement further comprises: determining a phase angle of the I channel energy peak and a phase angle of the Q channel energy peak based on phase angles at the discrete steps; and determining a test signal power measurement at the determined phase angle of the I channel energy peak and a test signal power measurement at the determined phase angle of the Q channel energy peak based on the test signal power measurements.
9. The radar system of claim 4 , wherein determining the phase and gain imbalance further comprises: determining a phase angle of the I channel energy peak and a phase angle of the Q channel energy peak based on phase angles at the discrete steps; determining I channel energy and Q channel energy at a first phase angle midway between the determined phase angle of the I channel energy peak and the determined phase angle of the Q channel energy peak; determining test signal power measurements at the first phase angle based on the test signal power measurements; and computing the phase imbalance using ∅ ^ = a sin ( Q _ ph 2 γ Ipk 2 ( θ Qpk ) Q _ pk 2 γ Qph 2 ( θ ph ) ) - a cos ( I _ ph 2 γ Ipk 2 ( θ Ipk ) I _ pk 2 γ Iph 2 ( θ ph ) ) wherein θ ph is the first phase angle, Ī ph 2 , Q ph 2 are the respective determined I and Q channel energies at θ ph , and γ Iph 2 (θ ph ), γ Qph 2 (θ ph ) are the respective determined test signal power measurements at θ ph .
10. A radar system comprising: a radar transceiver integrated circuit (IC) comprising receive channels, each receive channel comprising an in-phase (I) channel and a quadrature (Q) channel, wherein the radar transceiver IC is configured to send a test signal to the receive channels, in which a phase angle of the test signal is changed in discrete steps within a phase angle range, to collect energy measurements of the test signal output by the I channel and the Q channel of the receive channels at the phase angles, and to collect power measurements of the test signal for at least some of the phase angles; and a processor coupled to the radar transceiver IC, the processor configured to receive the energy measurements and the test signal power measurements, the processor configured to determine phase and gain imbalance of the I channel and the Q channel of the receive channels based on the energy measurements and the test signal power measurements.
11. The radar system of claim 10 , wherein the processor is comprised in the radar transceiver IC.
12. The radar system of claim 10 , wherein the radar transceiver IC further comprises: a transmit channel coupled to the receive channels via a feedback loop, the transmit channel configured to output the test signal; and a power detector coupled to the feedback loop, the power detector configured to measure power of the test signal output by the transmit channel.
13. The radar system of claim 10 , wherein determining the phase and gain imbalance of a receive channel comprises: determining an I channel energy peak from the energy measurements of the I channel and a Q channel energy peak from the energy measurements of the Q channel; determining a test signal power measurement at the I channel energy peak and a test signal power measurement at the Q channel energy peak based on the test signal power measurements; and computing the gain imbalance using α ^ = Q _ pk 2 γ Ipk 2 ( θ Ipk ) I _ pk 2 γ Qpk 2 ( θ Qpk ) wherein Ī pk 2 and Q pk 2 are respective energies of the I channel energy peak and the Q channel energy peak and γ Ipk 2 (θ Ipk ) and γ Qpk 2 (θ Qpk ) are respective determined test signal power measurements at the respective peaks.
14. The radar system of claim 13 , wherein determining the phase and gain imbalance of a receive channel further comprises: determining a phase angle of the I channel energy peak and a phase angle of the Q channel energy peak based on phase angles at the discrete steps; determining I channel energy and Q channel energy at a first phase angle midway between the determined phase angle of the I channel energy peak and the determined phase angle of the Q channel energy peak; determining test signal power measurements at the first phase angle based on the test signal power measurements; and computing the phase imbalance using ∅ ^ = a sin ( Q _ ph 2 γ Ipk 2 ( θ Qpk ) Q _ pk 2 γ Qph 2 ( θ ph ) ) - a cos ( I _ ph 2 γ Ipk 2 ( θ Ipk ) I _ pk 2 γ Iph 2 ( θ ph ) ) wherein θ ph is the first phase angle, Ī ph 2 , Q ph 2 are the respective determined I and Q channel energies at θ ph , and γ Iph 2 (θ ph ), γ Qph 2 (θ ph ) are the respective determined test signal power measurements at θ ph .
15. The radar system of claim 13 , wherein determining an I channel energy peak and a Q channel peak further comprises: determining an I channel coarse energy peak from the energy measurements of the I channel and of a Q channel coarse energy peak from the energy measurements of the Q channel; and interpolating around the I channel coarse energy peak and around the Q channel coarse energy peak to determine the respective I channel energy peak and Q channel energy peak.
16. The radar system of claim 15 , wherein an order of the interpolation is quadratic.
17. The radar system of claim 15 , wherein determining an I channel coarse energy peak and a Q channel coarse energy peak comprises selecting a largest energy measurement from the respective energy measurements having a previous energy measurement and a subsequent energy measurement as the respective coarse energy peak.
18. The radar system of claim 13 , wherein determining a test signal power measurement further comprises: determining a phase angle of the I channel energy peak and a phase angle of the Q channel energy peak based on phase angles at the discrete steps; and determining a test signal power measurement at the determined phase angle of the I channel energy peak and a test signal power measurement at the determined phase angle of the Q channel energy peak based on the test signal power measurements.
19. The radar system of claim 10 , wherein the phase angle range is 0° to 240° and each discrete step is 15°.
20. A method comprising: outputting, by a transmit channel of a radar system, a first test signal having a first phase angle; outputting, by the transmit channel, a second test signal, the second test signal having a second phase angle, wherein the first phase angle and the second phase angle are in a phase angle range and a phase difference between the first phase angle and the second phase angle is a discrete step size; receiving, by a receive channel of the radar system, the first test signal; generating, by the receive channel, a first in-phase (I) channel test signal in accordance with the first test signal; generating, by the receive channel, a first quadrature (Q) channel test signal in accordance with the first test signal; receiving, by the receive channel, the second test signal; generating, by the receive channel, a second I channel test signal in accordance with the second test signal; generating, by the receive channel, a second Q channel test signal in accordance with the second test signal; receiving, by a statistics collection module of the radar system, the first I channel test signal; measuring, by the statistics collection module, energy of the first I channel test signal; receiving, by the statistics collection module, the first Q channel test signal; measuring, by the statistics collection module, energy of the first Q channel test signal receiving, by the statistics collection module, the second I channel test signal; measuring, by the statistics collection module, energy of the second I channel test signal; receiving, by the statistics collection module, the second Q channel test signal; measuring, by the statistics collection module, the energy of the second Q channel test signal; and determining, by a control module of the radar system, gain and phase imbalance of the I channel and the Q channel based on the energy of the first I channel test signal, the energy of the first Q channel test signal, the energy of the second I channel test signal, and the energy of the second Q channel test signal.
21. The method of claim 20 , wherein the phase angle range is 0° to 240° and the discrete step is 15°.
22. The method of claim 20 , further comprising collecting power measurements of the test signal for the first phase angle and the second phase angle, wherein determining the gain and phase imbalance further comprises using the test signal power measurements.
23. The method of claim 22 , further comprising outputting, by a transmit channel of the radar system, by a feedback loop the first test signal and the second test signal.
24. The method of claim 22 , wherein determining the gain and phase imbalance further comprises: determining an I channel energy peak from the energy measurements of the I channel and a Q channel energy peak from the energy measurements of the Q channel; determining a test signal power measurement at the I channel energy peak and a test signal power measurement at the Q channel energy peak based on the test signal power measurements; and computing the gain imbalance using α ^ = Q _ pk 2 γ Ipk 2 ( θ Ipk ) I _ pk 2 γ Qpk 2 ( θ Qpk ) wherein Ī pk 2 and Q pk 2 are respective energies of the I channel energy peak and the Q channel energy peak and γ Ipk 2 (θ Ipk ) and γ Qpk 2 (θ Qpk ) are respective determined test signal power measurements at the respective peaks.
25. The method of claim 24 , wherein determining the gain and phase imbalance further comprises: determining a phase angle of the I channel energy peak and a phase angle of the Q channel energy peak based on phase angles at the discrete steps; determining I channel energy and Q channel energy at a first phase angle midway between the determined phase angle of the I channel energy peak and the determined phase angle of the Q channel energy peak; determining test signal power measurements at the first phase angle based on the test signal power measurements; and computing the phase imbalance using ∅ ^ = a sin ( Q _ ph 2 γ Ipk 2 ( θ Qpk ) Q _ pk 2 γ Qph 2 ( θ ph ) ) - a cos ( I _ ph 2 γ Ipk 2 ( θ Ipk ) I _ pk 2 γ Iph 2 ( θ ph ) ) wherein θ ph is the first phase angle, Ī ph 2 , Q ph 2 are the respective determined I and Q channel energies at θ ph , and γ Iph 2 (θ ph ), γ Qph 2 (θ ph ) are the respective determined test signal power measurements at θ ph .
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
June 29, 2017
October 27, 2020
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